<template>
  <div class="goods">
    <div class="menu-wrapper" v-el:menu-wrapper>
      <ul>
        <li v-for="item in goods" class="menu-item" :class="{'current':currentIndex===$index}"
            @click="selectMenu($index,$event)">
          <span class="text border-1px">
            <span v-show="item.type>0" class="icon" :class="classMap[item.type]"></span>{{item.name}}
            <!--v-show 判断子元素大于0才显示-->
          </span>
        </li>
      </ul>
    </div>
    <div class="foods-wrapper" v-el:foods-wrapper>
      <ul>
        <li v-for="item in goods" class="food-list food-list-hook">
          <h1 class="title">{{item.name}}</h1>
          <ul>
            <li @click="selectFood(food,$event)" v-for="food in item.foods" class="food-item border-1px">  <!--子元素列表-->
              <div class="icon">
                <img width="57" :src="food.icon" alt="">
              </div>
              <div class="content">
                <h2 class="name">{{food.name}}</h2> <!--标题-->
                <p class="desc">{{food.desc}}</p><!--一段描述内容-->
                <div class="extra">
                  <span class="count">月售{{food.sellCount}}</span>
                  <span>好评率{{food.rating}}</span>
                </div>
                <div class="price">
                  <span class="now">￥{{food.price}}</span><span class="old"
                                                                v-show="food.oldPrice">￥{{food.oldPrice}} </span>
                  <!--这个降价才有-->
                </div>
                <div class="cartcontrol-wrapper">
                  <cartcontrol :food="food" ></cartcontrol>   <!--v-ref:"food" 父组件要调用子组件的方法要加这个-->
                </div>

              </div>
            </li>
          </ul>
        </li>
      </ul>
    </div>
    <shopcart v-ref:shopcart :select-foods="selectFoods" :delivery-price="seller.deliveryPrice"
              :min-price="seller.minPrice"></shopcart>
  </div>
  <!--引用商品详情页 用变量selectFood控制-->
  <food :food="selectedFood" v-ref:food></food>
</template>

<script type="text/ecmascript-6">
  import BScroll from "better-scroll";

  //引入购物车组件
  import shopcart from 'components/shopcart/shopcart';
  import food from 'components/food/food';
  import cartcontrol from 'components/cartcontrol/cartcontrol';

  const ERR_OK = 0;

  export default {
    props: {
      seller: {
        type: Object
      }
    },
    data(){
      return {
        goods: [],
        listHeight: [],    //保存列表的高度属性   用来滚动
        scrollY: 0,
        selectedFood: {}
      }
    },
    computed: {
      currentIndex(){   //当scrollY变化是这里会实时变化
        for (let i = 0; i < this.listHeight.length; i++) {
          let height1 = this.listHeight[i];
          let height2 = this.listHeight[i + 1];
          if (!height2 || this.scrollY >= height1 && this.scrollY < height2) {
            return i;
          }
        }
        return 0;
      },
      selectFoods(){        //计算被选中的菜品
        let foods = [];
        this.goods.forEach((good) => {
          good.foods.forEach((food) => {
            if (food.count) {
              foods.push(food);
            }
          });
        });
        return foods;
      }
    },
    created(){
      //icon样式map
      this.classMap = ['decrease', 'discount', 'special', 'invoice', 'guarantee']
      //获取数据
      this.$http.get('/api/goods').then((response) => {
        response = response.body;
        if (response.errno === ERR_OK) {
          this.goods = response.data;
          //保证dom已经渲染了
          this.$nextTick(() => {
            this._initScroll()
            this._calculateHeight()
          })
        }
      });
    },
    methods: {
      selectFood(food, event){   //进入菜品详情页
        if (!event._constructed) {
          return;
        }
        this.selectedFood = food;
        //调用子组件的show方法
        this.$refs.food.show()
      },
      selectMenu(index, event){
        if (!event._constructed) {
          return;
        }
        let foodList = this.$els.foodsWrapper.getElementsByClassName('food-list-hook');
        let el = foodList[index];
        this.foodsScroll.scrollToElement(el, 300);
      },
      _initScroll(){   //滚动方法
        this.menuScroll = new BScroll(this.$els.menuWrapper, {
          click: true
        });
        this.foodsScroll = new BScroll(this.$els.foodsWrapper, {
          probeType: 3,
          click: true
        });

        //监听滚动位置
        this.foodsScroll.on('scroll', (pos) => {
          this.scrollY = Math.abs(Math.round(pos.y));
        });
      },
      _calculateHeight(){  //滚动初始化计算高度
        //获取到每一个li
        let foodList = this.$els.foodsWrapper.getElementsByClassName('food-list-hook');
        let height = 0;
        this.listHeight.push(height);
        for (let i = 0; i < foodList.length; i++) {
          let item = foodList[i];
          height += item.clientHeight;
          this.listHeight.push(height);
        }
      },
      //调用子组件的小球的方法
      _drop(target){
        //在子组件上添加  v-ref:shopcart
        this.$refs.shopcart.drop(target);
      }
    },
    components: {
      shopcart,
      cartcontrol,
      food
    },
    events: {
      'cart.add'(target){
        //小球触发派发的事件
        this._drop(target);
      }
    }
  };
</script>

<style lang="stylus" rel="stylesheet/stylus">

  @import "../../common/stylus/mixin.styl";
  #test
    border-1px(rgba(7, 17, 27, 0.1))

  //基本视口
  .goods
    display: flex
    position: absolute
    top: 174px
    bottom: 46px
    width: 100%
    overflow hidden
    .menu-wrapper
      flex: 0 0 80px
      width: 80px //必须要给这个
      background #f3f5f7
      .menu-item //标签没有class查找速度快 给li加class
        display: table //垂直居中
        height: 54px
        width 100%
        text-align center
        line-height: 14px
        &.current
          position: relative
          z-index 10
          margin-top -1px
          background: #fff
          font-weight: 700
          .text
            border-none()
        .icon
          display: inline-block
          vertical-align: top
          width: 12px
          height: 12px
          margin-right: 2px
          background-size: 12px 12px
          background-repeat: no-repeat
          &.decrease
            bg-image("decrease_3")
          &.discount
            bg-image("discount_3")
          &.guarantee
            bg-image("guarantee_3")
          &.invoice
            bg-image("invoice_3")
          &.special
            bg-image("special_3")

        .text
          display: table-cell //
          width: 56px
          vertical-align: middle //垂直居中
          border-1px(rgba(7, 17, 27, 0.1))
          font-size: 12px
    .foods-wrapper
      flex: 1
      .title
        padding-left: 14px
        height: 26px
        line-height: 26px
        border-left: 2px solid #d9dde1
        font-size: 12px
        color: rgb(147, 153, 159)
        background: #f3f5f7
      .food-item
        display: flex
        margin: 18px
        padding-bottom: 18px
        border-1px(rgba(7, 17, 27, 0.1))
        &:last-child //最后一个子元素不要下边框
          border-none()
          margin-bottom: 0
        .icon
          flex: 0 0 57px
          margin-right: 10px
        .content
          flex: 1
          .name
            margin: 2px 0 8px 0
            height: 14px
            line-height: 14px
            font-size: 14px
            color: rgb(7, 17, 27)
          .desc, .extra
            line-height: 10px
            font-size: 10px
            color: rgb(147, 153, 159)
          .desc
            margin-bottom: 8px
            line-height 12px
          .extra
            line-height: 10px
            .count
              margin-right 12px
          .price
            font-weight 700
            line-height: 24px
            .now
              margin-right: 8px
              font-size: 14px
              color: rgb(240, 20, 20)
            .old
              text-decoration line-through //删除线
              font-size: 10px
              color: rgb(147, 153, 159)
          .cartcontrol-wrapper
            position: absolute
            right: 0
            bottom: 12px
</style>
